title: Cost-effectiveness analysis of a new 8% capsaicin patch compared to existing therapies for postherpetic neuralgia.
abstract: OBJECTIVE
  The purpose of this study was to compare the cost effectiveness of a new 8% capsaicin patch, compared to the current treatments for postherpetic neuralgia (PHN), including tricyclic antidepressants (TCAs), topical lidocaine patches, duloxetine, gabapentin, and pregabalin.
  
  
  METHODS
  A 1-year Markov model was constructed for PHN with monthly cycles, including dose titration and management of adverse events. The perspective of the analysis was from a payer perspective, managed-care organization. Clinical trials were used to determine the proportion of patients achieving at least a 30% improvement in PHN pain, the efficacy parameter. The outcome was cost per quality-adjusted life-year (QALY); second-order probabilistic sensitivity analyses were conducted.
  
  
  RESULTS
  The effectiveness results indicated that 8% capsaicin patch and topical lidocaine patch were significantly more effective than the oral PHN products. TCAs were least costly and significantly less costly than duloxetine, pregabalin, topical lidocaine patch, 8% capsaicin patch, but not gabapentin. The incremental cost-effectiveness ratio for the 8% capsaicin patch overlapped with the topical lidocaine patch and was within the accepted threshold of cost per QALY gained compared to TCAs, duloxetine, gabapentin, and pregablin. The frequency of the 8% capsaicin patch retreatment assumption significantly impacts its cost-effectiveness results. There are several limitations to this analysis. Since no head-to-head studies were identified, this model used inputs from multiple clinical trials. Also, a last observation carried forward process was assumed to have continued for the duration of the model. Additionally, the trials with duloxetine may have over-predicted its efficacy in PHN. Although a 30% improvement in pain is often an endpoint in clinical trials, some patients may require greater or less improvement in pain to be considered a clinical success.
  
  
  CONCLUSIONS
  The effectiveness results demonstrated that 8% capsaicin and topical lidocaine patches had significantly higher effectiveness rates than the oral agents used to treat PHN. In addition, this cost-effectiveness analysis found that the 8% capsaicin patch was similar to topical lidocaine patch and within an accepted cost per QALY gained threshold compared to the oral products.
authors.affiliation: University of Arizona College of Pharmacy, Tucson, AZ 85721, USA. armstrong@pharmacy.arizona.edu
authors.forename: Edward P
authors.initials: EP
authors.lastname: Armstrong
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Malone
authors.forename: Bill
authors.initials: B
authors.lastname: McCarberg
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Panarites
authors.forename: Sissi V
authors.initials: SV
authors.lastname: Pham
mesh_terms: D000287:Administration, Topical; D000588:Amines / Q000008:administration & dosage / Q000191:economics; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000191:economics; D000929:Antidepressive Agents, Tricyclic / Q000008:administration & dosage / Q000191:economics; D002211:Capsaicin / Q000008:administration & dosage / Q000191:economics*; D002986:Clinical Trials as Topic; D003365:Costs and Cost Analysis; D003509:Cyclohexanecarboxylic Acids / Q000008:administration & dosage / Q000191:economics; D018765:Dopamine Uptake Inhibitors / Q000008:administration & dosage / Q000191:economics; D000068736:Duloxetine Hydrochloride; D018691:Excitatory Amino Acid Antagonists / Q000008:administration & dosage / Q000191:economics; D005260:Female; D000077206:Gabapentin; D006801:Humans; D008012:Lidocaine / Q000008:administration & dosage / Q000191:economics; D008297:Male; D008390:Markov Chains; D051474:Neuralgia, Postherpetic; D000069583:Pregabalin; D011788:Quality of Life; D018689:Sensory System Agents / Q000008:administration & dosage / Q000191:economics*; D013876:Thiophenes / Q000008:administration & dosage / Q000191:economics; D057968:Transdermal Patch / Q000191:economics*; D005680:gamma-Aminobutyric Acid / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000191:economics
chemical_list: D000588:Amines; D000779:Anesthetics, Local; D000929:Antidepressive Agents, Tricyclic; D003509:Cyclohexanecarboxylic Acids; D018765:Dopamine Uptake Inhibitors; D018691:Excitatory Amino Acid Antagonists; D018689:Sensory System Agents; D013876:Thiophenes; D000069583:Pregabalin; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin; D000068736:Duloxetine Hydrochloride; D008012:Lidocaine; D002211:Capsaicin